Compounds of the pyrazolanthrone series



Patented Dec. 27, 1938 UNITED STATES PATENT OFFlCE COMPOUNDS OF THE PYRAZOLANTHRO-NE SERIES Ralph N. Lulek, Milwaukee, and Earl E. Beard, South Milwaukee, Wis., assignors to E. I. du Pont de Nemours & Company, Wilmington, DeL, a corporation of Delaware No Drawing. Application February 24, 1936, Serial No. 65,420

4 Claims. (Cl. 260-312) This invention relates to the preparation of product is then filtered, washed acid free and new compounds of the pyrazolanthrone series dried. The new 1,9-pyrazolanthrone-6-carand more particularly to the preparation of 1,9- boxylic acid when in dry form is a greenishpyrazolanthrone-6-carboxylic acid and the acid yellow solid, very slightly soluble in nitrobenzene chloride. with a brownish-yellow color, and soluble in 5 We have found that l-amino-anthraquinonedilute caustic alkali with an orange to brown fi-carboxylic acid can be converted to a new and color. On fusing with alcoholic potash it gives a valuable dyestuif intermediate oi the pyrazolproduct which dyes cotton from a greenish-blue anthrone series by diazotizing the amino group, vat in strong yellow shades. The ring-closure of 10 reducing the diazo compound to the hydrazine the 1-hydrazino-anthraquinone-6-carboxylic 10 and then ring-closing the 1-hydrazino-anthraacid may be carried out in other acids, although quinone-S-carboxylic acid to the 1,9-pyrazolsulfuric acid is preferred. The temperature and anthrone-G-carboxylic acid. time may, of course, be varied within reasonable The diazotization and reduction of the diazo limits. }5 compound to the hydrazine may be carried out The 1,9-py a ar y c acid by the procedure generally employed for preparmay be converted to the 1,9-pyrazolanthrone-6- ing anthraquinone hydrazine from l-amino-ancarbonyl chloride by heating with thionyl chlothraquinone. The l-amino-anthraquinone-G- ride in an inert organic solvent such as orthocarboxylic acid used as the starting material may dichlorobenzene O1 nitrobenzene at 7 0-80 C.

be obtained by reduction of the l-nitro-anthra- We claim: 20 quinone-B-carboxylic acid of U. s. Patent As a new mp und, -py anthr n 1,991,191, in alkaline solution with an alkali metal containing in the 6 p t a up of t c a s hydrosulfite or sulfhydrate. consisting of COOH and -COCl.

The following example is given to more fully s a n w o p un -pyrazoIanthrone-6- 5 illustrate our invention. The parts used are by carboxylic acidweight. 3. As a new compound, 1,9-pyrazolanthrone-6- Example carbonyl chloride.

4. The process for preparing 1,9-pyraz01- Ten parts of 1-hydrazino-anthraquinone-6- anthronie-G-carboxylic acid which comprises carboxylic acid (obtained from l-amino-anthraheating 1-hydrazino-anthraquinoneefi-carboxylic 3O quinone-fi-carboxylic acid) are heated in '70 parts acid in acid solution to. elTect the formation of of 95% sulfuric acid at 125-130 C. for from 4 to 5 the pyrazole ring. hours. The reaction mass is then cooled and sufficient water is slowly added to reduce the sul- RALPH LULEK- furic acid concentration to about The EARL BEARD- 35 

